//
// Encog(tm) Core v3.1 - .Net Version
// http://www.heatonresearch.com/encog/
//
// Copyright 2008-2012 Heaton Research, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
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// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//   
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using Encog.ML.Genetic.Genes;
using Encog.ML.Genetic.Genome;
using Encog.MathUtil;

namespace Encog.ML.Genetic.Mutate
{
    /// <summary>
    /// A simple mutation based on random numbers.
    /// </summary>
    ///
    public class MutatePerturb : IMutate
    {
        /// <summary>
        /// The amount to perturb by.
        /// </summary>
        ///
        private readonly double _perturbAmount;

        /// <summary>
        /// Construct a perturb mutation.
        /// </summary>
        ///
        /// <param name="thePerturbAmount">The amount to mutate by(percent).</param>
        public MutatePerturb(double thePerturbAmount)
        {
            _perturbAmount = thePerturbAmount;
        }

        #region IMutate Members

        /// <summary>
        /// Perform a perturb mutation on the specified chromosome.
        /// </summary>
        ///
        /// <param name="chromosome">The chromosome to mutate.</param>
        public void PerformMutation(Chromosome chromosome)
        {
            foreach (IGene gene  in  chromosome.Genes)
            {
                if (gene is DoubleGene)
                {
                    var doubleGene = (DoubleGene) gene;
                    double v = doubleGene.Value;
                    v += (_perturbAmount - (ThreadSafeRandom.NextDouble()*_perturbAmount*2));
                    doubleGene.Value = v;
                }
            }
        }

        #endregion
    }
}
